JPH08129202A - Variable power finder optical system - Google Patents
Variable power finder optical systemInfo
- Publication number
- JPH08129202A JPH08129202A JP6290436A JP29043694A JPH08129202A JP H08129202 A JPH08129202 A JP H08129202A JP 6290436 A JP6290436 A JP 6290436A JP 29043694 A JP29043694 A JP 29043694A JP H08129202 A JPH08129202 A JP H08129202A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- group
- refractive power
- variable
- optical system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/163—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
- G02B15/167—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
- G02B15/173—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/145—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only
- G02B15/1451—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only the first group being positive
- G02B15/145113—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only the first group being positive arranged +-++-
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/146—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having more than five groups
- G02B15/1461—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having more than five groups the first group being positive
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Viewfinders (AREA)
- Lenses (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は変倍ファインダー光学系
に関し、特に撮影系（撮影レンズ）とは別体に設けた外
部式のファインダー光学系のレンズ構成を適切に設定
し、種々の倍率でファインダー像の良好なる観察を可能
とした、例えばスチルカメラやビデオカメラ等に好適な
実像式の変倍ファインダー光学系に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable-magnification finder optical system, and in particular, an external finder optical system provided separately from a photographing system (photographing lens) is appropriately set to obtain various magnifications. The present invention relates to a variable magnification finder optical system of a real image type which is suitable for, for example, still cameras and video cameras, and which enables good observation of finder images.
【０００２】[0002]
【従来の技術】従来より撮影系とファインダー光学系が
別体に構成されているカメラでは撮影系が変倍系のとき
には変倍に伴いファインダー視野倍率が変化する構成の
変倍ファインダーが、撮影上好ましい。又変倍ファイン
ダーはカメラに組込むことから小型でしかも所定の変倍
比が容易に得られる構成のものが好ましい。2. Description of the Related Art Conventionally, in a camera in which a photographing system and a viewfinder optical system are separately configured, when the photographing system is a variable magnification system, a variable magnification viewfinder having a structure in which the viewfinder field magnification changes with the magnification change preferable. Further, since the variable power finder is incorporated in the camera, it is preferable that the variable power finder has a small size and can easily obtain a predetermined variable power ratio.
【０００３】又変倍ファインダー光学系のうち実像式の
変倍ファインダー光学系は正の屈折力の対物レンズで１
次結像面上に形成したファインダー像をポロプリズム等
の像反転手段を介して接眼レンズで観察する構成を用い
ている。この為、１次結像面に視野マスクを配置するこ
とができる為にファインダー視野の輪郭を観察者の瞳位
置を動かしても明瞭に観察することができるといった特
長がある。Of the variable magnification finder optical systems, the real image type variable magnification finder optical system is an objective lens having a positive refractive power.
A structure is used in which the finder image formed on the next image forming surface is observed by an eyepiece through image inverting means such as a Porro prism. For this reason, since the visual field mask can be arranged on the primary image plane, the contour of the finder visual field can be clearly observed even if the observer's pupil position is moved.
【０００４】実像式の変倍ファインダー光学系として、
例えば特開平３−８７８０３号公報では対物レンズを物
体側より順に正，負，正、そして正の屈折力の第１，第
２，第３，第４群の４つのレンズ群より構成し、第２，
第３群を光軸上移動させて変倍を行っている。As a real image type variable magnification finder optical system,
For example, in Japanese Unexamined Patent Publication No. 3-87803, an objective lens is composed of four lens groups of positive, negative, positive, and positive refractive powers in order from the object side. Two
The third group is moved on the optical axis to change the magnification.
【０００５】又特開平５−３４１１８７号公報では対物
レンズを物体側より順に正，負，正、そして正の屈折力
の第１，第２，第３，第４群の４つのレンズ群より構成
し、第２，第４群を光軸上移動させて変倍を行ってい
る。Further, in Japanese Unexamined Patent Publication No. 5-341187, an objective lens is composed of four lens groups of positive, negative, positive, and positive refracting powers in order from the object side. Then, the second and fourth groups are moved on the optical axis to change the magnification.
【０００６】[0006]
【発明が解決しようとする課題】近年、液晶モニター付
のビデオカメラ等においては消費電力がなるべく少なく
なるようにファインダー系として電子式ファインダーに
比べて光学式ファインダーが多く用いられてきている。
そしてこれらの変倍ファインダー光学系に要求される事
項として撮影レンズの変倍比と略同じ変倍比を有するこ
と、レンズ系全体が小型であること等がある。In recent years, in a video camera with a liquid crystal monitor or the like, an optical finder has been widely used as a finder system as compared with an electronic finder so as to reduce power consumption as much as possible.
The requirements for these variable power finder optical systems are that they have a variable power ratio that is approximately the same as the variable power ratio of the taking lens, and that the entire lens system is compact.
【０００７】例えばビデオカメラでは変倍比が６倍程度
の小型の変倍ファインダー光学系が要望されている。一
般に変倍用の各レンズ群の屈折力を強めたり、移動量を
多くしたり、又移動レンズ群の数を増加させれば高変倍
化が達成される。[0007] For example, in a video camera, there is a demand for a compact variable-magnification finder optical system having a variable-magnification ratio of about 6 times. In general, high magnification can be achieved by increasing the refractive power of each lens unit for zooming, increasing the amount of movement, or increasing the number of moving lens units.
【０００８】しかしながら、各レンズ群の屈折力を強め
ると変倍に伴う収差変動が大きくなり、全変倍範囲にわ
たり高い光学性能を得るのが難しくなってくる。又変倍
用レンズ群の移動量を増やしたり、変倍用のレンズ群の
数を増やすとレンズ全長が長くなり、ファインダー系全
体が大型化するという問題点が生じてくる。However, if the refracting power of each lens unit is strengthened, the variation of aberrations due to zooming becomes large, and it becomes difficult to obtain high optical performance over the entire zooming range. Further, if the amount of movement of the zoom lens group is increased or the number of zoom lens groups is increased, the total length of the lens becomes longer and the viewfinder system becomes larger.
【０００９】本発明は、変倍部を有する対物レンズのレ
ンズ構成を適切に設定することにより、比較的簡易なレ
ンズ構成により変倍比６倍程度と高変倍比を有し、かつ
全変倍範囲にわたり高い光学性能を有した、例えばスチ
ルカメラやビデオカメラ等に好適な実像式の変倍ファイ
ンダー光学系の提供を目的とする。According to the present invention, by appropriately setting the lens configuration of the objective lens having the variable power portion, the variable power ratio is about 6 times and the high variable power ratio is achieved by a relatively simple lens configuration, and the total variable power is achieved. It is an object of the present invention to provide a real image type variable magnification finder optical system having high optical performance over a doubling range and suitable for, for example, still cameras and video cameras.
【００１０】[0010]
【課題を解決するための手段】本発明の変倍ファインダ
ー光学系は、 （１−１）対物レンズによって形成した物体像を接眼レ
ンズを介して観察する際、物体側より順に該対物レンズ
は固定の正の屈折力の第１群、変倍用の負の屈折力の第
２群、少なくとも１つの固定の正の屈折力の第３群、変
倍に伴う像面変動の補正をすると共に合焦作用をする正
の屈折力の第４群、そして固定の負の屈折力の第５群を
有していることを特徴としている。The variable magnification finder optical system of the present invention comprises: (1-1) When observing an object image formed by an objective lens through an eyepiece, the objective lens is fixed in order from the object side. Of the positive refractive power, the second group of the negative refractive power for zooming, the third group of at least one fixed positive refractive power, It is characterized in that it has a fourth lens unit having a positive refractive power for performing a focal action and a fifth lens unit having a fixed negative refractive power.
【００１１】（１−２）対物レンズによって形成した物
体像を接眼レンズを介して観察する際、物体側より順に
該対物レンズは固定の正の屈折力の第１群、可動の負の
屈折力の第２群、固定の正の屈折力の第３群、可動の正
の屈折力の第４群、そして固定の負の屈折力の第５群の
５つのレンズ群を有し、該第２群と第４群を光軸上移動
させて変倍及び合焦作用を行っていることを特徴として
いる。(1-2) When observing an object image formed by the objective lens through the eyepiece lens, the objective lens has a fixed positive refractive power first group and a movable negative refractive power in order from the object side. A second lens unit having a fixed positive refractive power, a third lens unit having a fixed positive refractive power, a fourth lens unit having a movable positive refractive power, and a fifth lens unit having a fixed negative refractive power, It is characterized in that the lens unit and the fourth lens unit are moved on the optical axis to perform zooming and focusing.
【００１２】（１−３）対物レンズによって形成した物
体像を接眼レンズを介して観察する際、物体側より順に
該対物レンズは固定の正の屈折力の第１群、可動の負の
屈折力の第２群、可動の第３群、固定の正の屈折力の第
４群、可動の正の屈折力の第５群、そして固定の負の屈
折力の第６群の６つのレンズ群を有し、該第２，第３，
第５群を光軸上移動させて変倍及び合焦作用を行ってい
ることを特徴としている。(1-3) When observing an object image formed by an objective lens through an eyepiece, the objective lens has a fixed positive refractive power first group and a movable negative refractive power in order from the object side. A second lens group, a movable third lens group, a fixed positive refractive power fourth lens group, a movable positive refractive power fifth lens group, and a fixed negative refractive power sixth lens group. Having, the second, third,
It is characterized in that the fifth lens group is moved on the optical axis to perform zooming and focusing.
【００１３】[0013]
【実施例】図１，図２は各々本発明の後述する数値実施
例１，３の光学系の光路を展開したときのレンズ断面図
である。図１，図２においてＬ０は対物レンズであり、
変倍部を有している。Ｐは１次結像面であり、対物レン
ズＬ０による物体像（ファインダー像）が形成されてい
る。Ｇは像反転手段である。同図では入射面Ｇａに所定
の正の屈折力を有すると共に反射面と全反射面（不図
示）を有したポロプリズム等から成っている場合を示し
ている。同図では光路を展開したブロックを示してい
る。ＬＥは接眼レンズである。ＥＰは観察用のアイポイ
ントである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are sectional views of lenses when the optical paths of optical systems of Numerical Examples 1 and 3 to be described later of the present invention are developed. 1 and 2, L0 is an objective lens,
It has a variable power section. P is a primary image plane, on which an object image (finder image) is formed by the objective lens L0. G is an image inverting means. The figure shows a case where the incident surface Ga is composed of a Porro prism or the like having a predetermined positive refractive power and a reflecting surface and a total reflecting surface (not shown). In the same figure, the block which expanded the optical path is shown. LE is an eyepiece. EP is an eyepoint for observation.
【００１４】本実施例では変倍部を有する対物レンズＬ
０で１次結像面Ｐに形成した種々の倍率のファインダー
像を像反転手段Ｇを介して正立のファインダー像として
接眼レンズＬＥを介してアイポイントＥＰより観察して
いる。In this embodiment, the objective lens L having a variable power portion is used.
The viewfinder images of various magnifications formed on the primary image formation plane P at 0 are observed as an upright viewfinder image through the image inverting means G from the eyepoint EP through the eyepiece lens LE.
【００１５】尚本実施例において像反転手段をエレクタ
ーレンズ等の再結像レンズより構成して該エレクターレ
ンズにより１次結像面Ｐに形成した倒立の物体像を正立
正像として２次結像面に形成しても良い。そして２次結
像面に形成した正立正像のファインダー像を接眼レンズ
を介して観察するようにしても良い。In the present embodiment, the image inverting means is composed of a re-imaging lens such as an erector lens, and the inverted object image formed on the primary imaging plane P by the erector lens is erected as an erected normal image and secondary imaged. It may be formed on the surface. Then, the finder image of an erect normal image formed on the secondary image plane may be observed through the eyepiece lens.
【００１６】次に図１，図２の対物レンズＬ０のレンズ
構成の特長について説明する。Next, the features of the lens configuration of the objective lens L0 shown in FIGS. 1 and 2 will be described.
【００１７】図１において対物レンズＬ０は固定の正の
屈折力の第１群、変倍用の負の屈折力の第２群、固定の
正の屈折力の第３群、変倍に伴う像面変動の補正と合焦
作用（フォーカス）を行う正の屈折力の第４群、そして
固定の負の屈折力の第５群の５つのレンズ群より成って
いる。In FIG. 1, the objective lens L0 is a fixed first refractive power first group, a negative refractive power second group for zooming, a fixed positive refractive power third group, and an image associated with zooming. It is composed of five lens groups, a fourth lens group having a positive refractive power and a fifth lens group having a fixed negative refractive power, which corrects a surface variation and focuses.
【００１８】本実施例では撮影レンズ（不図示）の広角
端から望遠端への変倍に際してそれに対応させて矢印の
ように第２群Ｌ２を像面側へ移動させると共に、変倍に
伴う像面変動を第４群Ｌ４を移動させて補正している。In the present embodiment, the second lens unit L2 is moved to the image plane side as indicated by the arrow in correspondence with the magnification change from the wide-angle end to the telephoto end of the taking lens (not shown), and the image accompanying the magnification change is made. The surface variation is corrected by moving the fourth lens unit L4.
【００１９】本実施例のように変倍比が大きくなると、
望遠側では物体距離の変化に伴いファインダー視度が変
動してくる。When the variable power ratio becomes large as in this embodiment,
On the telephoto side, the viewfinder diopter changes as the object distance changes.
【００２０】そこで本実施例では第４群を光軸上移動さ
せて物体距離の変動に伴うファインダー視度の変動を補
正している。Therefore, in this embodiment, the fourth group is moved on the optical axis to correct the change in the finder diopter caused by the change in the object distance.
【００２１】同図に示す第４群の実線の曲線４ａと点線
の曲線４ｂは各々無限遠物体と近距離物体にフォーカス
しているときの広角端から望遠端への変倍に伴う際の像
面変動を補正する為の移動軌跡を示している。The solid curve 4a and the dotted curve 4b of the fourth group shown in the same figure are images at the time of zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and a near object, respectively. The movement locus for correcting the surface variation is shown.
【００２２】本実施例においては第４群を移動させて変
倍に伴う像面変動の補正を行うと共に第４群を移動させ
てフォーカスを行うようにしている。特に同図の曲線４
ａ，４ｂに示すように広角端から望遠端への変倍に際し
て物体側へ凸状の軌跡を有するように移動させている。
これにより第３群と第４群との空間の有効利用を図りレ
ンズ全長の短縮化を効果的に達成している。In the present embodiment, the fourth lens unit is moved to correct the image plane variation due to zooming, and the fourth lens unit is moved to perform focusing. Curve 4 in the figure
As indicated by a and 4b, the zoom lens is moved so as to have a convex locus toward the object side during zooming from the wide-angle end to the telephoto end.
As a result, the space between the third group and the fourth group is effectively used, and the total lens length is effectively shortened.
【００２３】本実施例において、例えば望遠端において
無限遠物体から近距離物体へフォーカスを行う場合は同
図の直線４ｃに示すように第４群を前方へ繰り出すこと
により行っている。In the present embodiment, for example, when focusing from an object at infinity to a near object at the telephoto end, the fourth lens unit is moved forward as indicated by a straight line 4c in the figure.
【００２４】本実施例では第４群Ｌ４の後方に負の屈折
力の第５群を設けて、対物レンズＬ０全体が望遠型とな
るようにして、レンズ全長の短縮化を図ると共に諸収
差、特に色収差を良好に補正している。In the present embodiment, a fifth lens unit having a negative refractive power is provided behind the fourth lens unit L4 so that the entire objective lens L0 is of a telephoto type, so that the total lens length is shortened and various aberrations are caused. Especially chromatic aberration is corrected well.
【００２５】本実施例では物体側より順に第１群Ｌ１を
物体側に凸面を向けたメニスカス状の負レンズ、両レン
ズ面が凸面の２つの正レンズより構成して、望遠側での
軸上色収差と倍率色収差、そして球面収差等を良好に補
正している。In this embodiment, the first unit L1 is composed of a negative meniscus lens having a convex surface facing the object side and two positive lenses having convex lens surfaces on the axial side on the telephoto side. The chromatic aberration, the chromatic aberration of magnification, and the spherical aberration are well corrected.
【００２６】第２群Ｌ２を両レンズ面が凹面の２つの負
レンズより構成して広角側での歪曲収差、望遠側での球
面収差とコマ収差等を良好に補正している。The second lens unit L2 is composed of two negative lenses each having a concave lens surface, and satisfactorily corrects distortion on the wide-angle side, spherical aberration on the telephoto side, and coma.
【００２７】第３群Ｌ３を両レンズ面が凸面の単一の正
レンズより構成し、第４群Ｌ４を両レンズ面が凸面の単
一の正レンズより構成し、そして第５群Ｌ５を両レンズ
面が凹面の単一の負レンズより構成し、これによりレン
ズ構成の簡素化を図りつつ、全変倍範囲にわたり収差変
動を少なくし、高い光学性能を得ている。又前記第１群
はガラス材より成る正レンズとプラスチック材より成る
正レンズとを有し、前記第２群はプラスチック材より成
るレンズで構成して、これによりレンズ系全体の軽量化
を図りつつ、温度変化があったときの光学特性の変動、
例えば望遠側における視度等の変動を少なくしている。The third lens unit L3 is composed of a single positive lens whose both lens surfaces are convex, the fourth lens unit L4 is composed of a single positive lens whose both lens surfaces are convex, and the fifth lens unit L5 is composed of both. It is composed of a single negative lens whose concave lens surface is concave. This simplifies the lens structure, reduces aberration variation over the entire zoom range, and obtains high optical performance. The first group has a positive lens made of a glass material and a positive lens made of a plastic material, and the second group is made of a lens made of a plastic material, thereby reducing the weight of the entire lens system. , Fluctuation of optical characteristics when there is a temperature change,
For example, the variation of diopter on the telephoto side is reduced.
【００２８】図２において対物レンズＬ０は固定の正の
屈折力の第１群、変倍用の負の屈折力の第２群、変倍に
伴う像面変動の補正と合焦作用（フォーカス）を行う負
の屈折力の第３群と正の屈折力の第５群、固定の正の屈
折力の第４群、そして固定の負の屈折力の第６群の６つ
のレンズ群より成っている。In FIG. 2, an objective lens L0 is a first lens unit having a fixed positive refractive power, a second lens unit having a negative refractive power for zooming, correction of an image plane variation due to zooming, and a focusing action (focus). Consisting of six lens groups, a negative refractive power third group, a positive refractive power fifth group, a fixed positive refractive power fourth group, and a fixed negative refractive power sixth group. There is.
【００２９】本実施例では撮影レンズ（不図示）の広角
端から望遠端への変倍に際してそれに対応させて矢印の
ように第２群Ｌ２を像面側へ移動させると共に、変倍に
伴う像面変動を第３群Ｌ３と第５群Ｌ５を移動させて補
正している。In this embodiment, the second lens unit L2 is moved to the image plane side as indicated by the arrow in correspondence with the magnification change from the wide-angle end to the telephoto end of the taking lens (not shown), and the image associated with the magnification change is made. The surface variation is corrected by moving the third lens unit L3 and the fifth lens unit L5.
【００３０】本実施例のように変倍比が大きくなると、
望遠側では物体距離の変化に伴いファインダー視度が変
動してくる。When the variable power ratio becomes large as in this embodiment,
On the telephoto side, the viewfinder diopter changes as the object distance changes.
【００３１】そこで本実施例では第３群と第５群を光軸
上移動させて物体距離の変動に伴うファインダー視度の
変動を補正している。Therefore, in this embodiment, the third group and the fifth group are moved on the optical axis to correct the change in the finder diopter caused by the change in the object distance.
【００３２】本実施例では変倍及びフォーカスの際に第
３群と第５群とを一体的に光軸上移動させているが、互
いに独立に移動させても良い。In the present embodiment, the third group and the fifth group are integrally moved on the optical axis during zooming and focusing, but they may be moved independently of each other.
【００３３】同図に示す第３群の実線の曲線３ａと点線
の曲線３ｂ、そして第５群の実線の曲線５ａと点線の曲
線５ｂは各々無限遠物体と近距離物体にフォーカスして
いるときの広角端から望遠端への変倍に伴う際の像面変
動を補正する為の移動軌跡を示している。The solid curve 3a and the dotted curve 3b of the third group, and the solid curve 5a and the dotted curve 5b of the fifth group shown in FIG. 3 are focused on an infinite object and a short-distance object, respectively. 7 shows a movement locus for correcting an image plane variation due to zooming from the wide-angle end to the telephoto end.
【００３４】本実施例においては第３群と第５群を移動
させて変倍に伴う像面変動の補正を行うと共に第３群と
第５群を移動させてフォーカスを行うようにしている。
特に同図の曲線３ａ，３ｂ，５ａ，５ｂに示すように広
角端から望遠端への変倍に際して物体側へ凸状の軌跡を
有するように移動させている。これにより第２群と第３
群との空間及び第４群と第５群との空間の有効利用を図
りレンズ全長の短縮化を効果的に達成している。In this embodiment, the third group and the fifth group are moved to correct the image plane variation due to the magnification change, and the third group and the fifth group are moved to perform the focusing.
In particular, as shown by the curves 3a, 3b, 5a, 5b in the figure, the lens is moved so as to have a convex locus toward the object side during zooming from the wide-angle end to the telephoto end. As a result, the second group and the third group
By effectively utilizing the space between the lens unit and the space between the fourth lens unit and the fifth lens unit, the overall lens length is effectively shortened.
【００３５】本実施例において、例えば望遠端において
無限遠物体から近距離物体へフォーカスを行う場合は同
図の直線３ｃ，５ｃに示すように第３群と第５群を前方
へ繰り出すことにより行っている。In the present embodiment, for example, when focusing on an object at infinity from a near object at the telephoto end, the third and fifth groups are moved forward as indicated by straight lines 3c and 5c in the figure. ing.
【００３６】本実施例では変倍に伴う像面変動の補正の
際に負の屈折力の第３群と正の屈折力の第５群を移動さ
せるようにして高変倍化を図る際のレンズ群の移動量を
少なくしている。又負の屈折力の第３群により変倍に伴
う球面収差とコマ収差を良好に補正している。In this embodiment, when correcting the image plane variation due to zooming, the third lens group having a negative refractive power and the fifth lens group having a positive refractive power are moved to achieve a high zooming ratio. The amount of movement of the lens group is reduced. Further, the third lens unit having a negative refracting power satisfactorily corrects spherical aberration and coma aberration due to zooming.
【００３７】本実施例では物体側より順に第１群Ｌ１を
物体側に凸面を向けたメニスカス状の負レンズ、両レン
ズ面が凸面の２つの正レンズより構成して、望遠側での
軸上色収差と倍率色収差、そして球面収差等を良好に補
正している。In this embodiment, the first lens unit L1 is composed of a negative meniscus lens having a convex surface directed toward the object side and two positive lenses having convex lens surfaces on the axial side on the telephoto side. The chromatic aberration, the chromatic aberration of magnification, and the spherical aberration are well corrected.
【００３８】第２群Ｌ２を両レンズ面が凹面の２つの負
レンズより構成して広角側での歪曲収差、望遠側での球
面収差とコマ収差等を良好に補正している。The second lens unit L2 is composed of two negative lenses each having a concave lens surface, and satisfactorily corrects distortion aberration on the wide-angle side, spherical aberration on the telephoto side, and coma.
【００３９】第３群Ｌ３を単一の負レンズより構成し、
第４群Ｌ４を両レンズ面が凸面の単一の正レンズより構
成し、第５群Ｌ５を両レンズ面が凸面の単一の正レンズ
より構成し、そして第６群Ｌ６を両レンズ面が凹面の単
一の負レンズより構成し、これによりレンズ構成の簡素
化を図りつつ、全変倍範囲にわたり収差変動を少なく
し、高い光学性能を得ている。又前記第１群はガラス材
より成る正レンズとプラスチック材より成る正レンズと
を有し、前記第２群はプラスチック材より成るレンズで
構成して、これによりレンズ系全体の軽量化を図りつ
つ、温度変化があったときの光学特性の変動、例えば望
遠側における視度等の変動を少なくしている。The third lens unit L3 is composed of a single negative lens,
The fourth lens unit L4 is composed of a single positive lens whose both lens surfaces are convex, the fifth lens unit L5 is composed of a single positive lens whose both lens surfaces are convex, and the sixth lens unit L6 is composed of both lens surfaces. It is composed of a single negative lens having a concave surface, which simplifies the lens structure, reduces aberration variation over the entire zoom range, and obtains high optical performance. The first group has a positive lens made of a glass material and a positive lens made of a plastic material, and the second group is made of a lens made of a plastic material, thereby reducing the weight of the entire lens system. The fluctuation of the optical characteristics when there is a temperature change, for example, the fluctuation of the diopter on the telephoto side is reduced.
【００４０】本発明の目的とする変倍ファインダー光学
系は以上の如く各要素を設定することにより達成してい
るが更に好ましくは次の条件を満足するのが良い。The variable-magnification finder optical system aimed at by the present invention is achieved by setting each element as described above, but it is more preferable to satisfy the following conditions.
【００４１】前記第２群の焦点距離をｆ２、広角端にお
ける前記対物レンズの焦点距離をｆｗとするとき ０．４＜｜ｆ２／ｆｗ｜＜０．６ ‥‥‥（１） なる条件を満足することである。When the focal length of the second lens unit is f2 and the focal length of the objective lens at the wide-angle end is fw, the condition 0.4 <| f2 / fw | <0.6 (1) is satisfied. It is to be.
【００４２】条件式（１）は高変倍化を図りつつ、対物
レンズのレンズ全長の短縮化を達成する為のものであ
る。条件式（１）の下限値を越えて第２群の屈折力が強
くなりすぎるとレンズ全長は短くなるが変倍に伴う収差
変動、特に像面弯曲や歪曲の変動が大きくなってくるの
で良くない。Conditional expression (1) is for achieving reduction of the total lens length of the objective lens while achieving high zooming. If the lower limit of conditional expression (1) is exceeded and the refracting power of the second lens group becomes too strong, the total lens length will be shortened, but aberration fluctuations due to zooming, especially fluctuations in image plane distortion and distortion, will increase. Absent.
【００４３】又条件式（１）の上限値を越えて第２群の
屈折力が弱くなりすぎると変倍に伴う収差変動の補正は
容易になるがレンズ全長が長くなると共に第１群の有効
径が増大してくるので良くない。When the upper limit of conditional expression (1) is exceeded and the refracting power of the second lens unit becomes too weak, it becomes easy to correct aberration fluctuations due to zooming, but the total lens length becomes long and the first lens unit is effective. It is not good because the diameter increases.
【００４４】尚本発明の変倍ファインダー光学系を組み
入れたカメラでは撮影レンズを変倍ファインダー光学系
とを同様のズームタイプより構成し、撮影レンズの変倍
用のレンズ群と変倍ファインダー光学系の第２群（変倍
レンズ群）とを機械的に連結し、又撮影レンズの像面変
動補正用のレンズ群と変倍ファインダー光学系の像面補
正用レンズ群とを機械的に連結することにより変倍ファ
インダー光学系には駆動手段を設けずに、撮影レンズの
駆動手段を利用して変倍及びフォーカスを行っている。In the camera incorporating the variable magnification finder optical system of the present invention, the photographing lens is constituted by the same zoom type as the variable magnification finder optical system, and the lens group for varying the magnification of the photographing lens and the variable magnification finder optical system are used. The second lens group (variable magnification lens group) is mechanically coupled, and the lens group for image plane variation correction of the taking lens and the image plane compensation lens group of the magnification finder optical system are mechanically coupled. As a result, the zooming finder optical system is not provided with a driving unit, and the zooming and focusing are performed by using the driving unit of the photographing lens.
【００４５】特に撮影レンズの変倍部と変倍ファインダ
ー光学系の変倍部における各レンズ群の移動量が変倍及
びフォーカスの際に略等しくなるようにして、これによ
りレンズ鏡筒の簡素化を図っている。In particular, the amount of movement of each lens unit in the variable power portion of the taking lens and the variable power portion of the variable power finder optical system is made substantially equal during zooming and focusing, thereby simplifying the lens barrel. I am trying to
【００４６】次に本発明の数値実施例を示す。数値実施
例においてｒｉは物体側より順に第ｉ番目のレンズ面の
曲率半径、ｄｉは物体側より順に第ｉ番目のレンズ厚及
び空気間隔、ｎｉとνｉは各々物体側より順に第ｉ番目
のレンズのガラスの屈折率とアッベ数である。Next, numerical examples of the present invention will be shown. In the numerical examples, ri is the radius of curvature of the i-th lens surface in order from the object side, di is the i-th lens thickness and air gap in order from the object side, and ni and vi are the i-th lens in order from the object side, respectively. Is the refractive index and Abbe number of the glass.
【００４７】非球面形状は光軸方向にＸ軸、光軸と垂直
方向にＨ軸、光の進行方向を正とし、Ｒを近軸曲率半
径、Ｂ，Ｃ，Ｄ，Ｅを各々非球面係数としたときThe aspherical shape has an X axis in the optical axis direction, an H axis in the direction perpendicular to the optical axis, a light traveling direction is positive, R is a paraxial radius of curvature, and B, C, D, and E are aspherical surface coefficients. When
【００４８】[0048]
【数１】 なる式で表している。又「Ｄ−０Ｘ」は「１０-X」を意
味している。[Equation 1] It is expressed by the formula. Also, "D-0X" means "10 -X ".
【００４９】[0049]
【外１】 [Outside 1]
【００５０】[0050]
【外２】 [Outside 2]
【００５１】[0051]
【外３】 [Outside 3]
【００５２】[0052]
【外４】 [Outside 4]
【００５３】[0053]
【発明の効果】本発明によれば以上のように、変倍部を
有する対物レンズのレンズ構成を適切に設定することに
より、比較的簡易なレンズ構成により変倍比６倍程度と
高変倍比を有し、かつ全変倍範囲にわたり高い光学性能
を有した、例えばスチルカメラやビデオカメラ等に好適
な実像式の変倍ファインダー光学系を達成することがで
きる。As described above, according to the present invention, by appropriately setting the lens configuration of the objective lens having the variable power portion, the variable power ratio is about 6 times and the high variable power is achieved with a relatively simple lens configuration. It is possible to achieve a variable magnification finder optical system of a real image type which has a high ratio and a high optical performance over the entire variable power range and which is suitable for, for example, still cameras and video cameras.
【図１】本発明の数値実施例１のレンズ断面図FIG. 1 is a lens cross-sectional view of Numerical Example 1 of the present invention.
【図２】本発明の数値実施例３のレンズ断面図FIG. 2 is a lens cross-sectional view of Numerical Example 3 of the present invention.
【図３】本発明の数値実施例１の広角端の収差図FIG. 3 is an aberration diagram at a wide-angle end according to Numerical Example 1 of the present invention.
【図４】本発明の数値実施例１の中間の収差図FIG. 4 is an intermediate aberration diagram of Numerical Example 1 of the present invention.
【図５】本発明の数値実施例１の望遠端の収差図FIG. 5 is an aberration diagram at a telephoto end according to Numerical Example 1 of the present invention.
【図６】本発明の数値実施例２の広角端の収差図FIG. 6 is an aberration diagram at the wide-angle end according to Numerical Example 2 of the present invention.
【図７】本発明の数値実施例２の中間の収差図FIG. 7 is an intermediate aberration diagram of Numerical example 2 of the present invention.
【図８】本発明の数値実施例２の望遠端の収差図FIG. 8 is an aberration diagram at a telephoto end according to Numerical Example 2 of the present invention.
【図９】本発明の数値実施例３の広角端の収差図FIG. 9 is an aberration diagram at a wide-angle end according to Numerical Example 3 of the present invention.
【図１０】本発明の数値実施例３の中間の収差図FIG. 10 is an intermediate aberration diagram of Numerical example 3 of the present invention.
【図１１】本発明の数値実施例３の望遠端の収差図FIG. 11 is an aberration diagram at a telephoto end according to Numerical Example 3 of the present invention.
【図１２】本発明の数値実施例４の広角端の収差図FIG. 12 is an aberration diagram at a wide-angle end according to Numerical Example 4 of the present invention.
【図１３】本発明の数値実施例４の中間の収差図FIG. 13 is an intermediate aberration diagram of Numerical Example 4 of the present invention.
【図１４】本発明の数値実施例４の望遠端の収差図FIG. 14 is an aberration diagram at a telephoto end according to Numerical Example 4 of the present invention.
Ｌ０ 対物レンズ ＬＥ 接眼レンズ Ｇ 第１結像面 ＥＰ アイポイント Ｌ１ 第１群 Ｌ２ 第２群 Ｌ３ 第３群 Ｌ４ 第４群 Ｌ５ 第５群 Ｌ６ 第６群 ｄ ｄ線 Ｆ Ｆ線 Ｓ サジタル像面 Ｍ メリディオナル像面 ｈ 瞳の高さ L0 Objective lens LE Eyepiece G G 1st image plane EP Eyepoint L 1 1st group L2 2nd group L3 3rd group L4 4th group L5 5th group L6 6th group d d line F F line S sagittal image plane M Meridional image plane h pupil height
Claims (8)
眼レンズを介して観察する際、物体側より順に該対物レ
ンズは固定の正の屈折力の第１群、変倍用の負の屈折力
の第２群、少なくとも１つの固定の正の屈折力の第３
群、変倍に伴う像面変動の補正をすると共に合焦作用を
する正の屈折力の第４群、そして固定の負の屈折力の第
５群を有していることを特徴とする変倍ファインダー光
学系。1. When observing an object image formed by an objective lens through an eyepiece lens, the objective lens has a fixed first refractive power group in order from the object side and a negative refractive power group for zooming. Second group, at least one fixed positive refractive power third
A lens unit, a fourth lens unit having a positive refractive power which corrects an image plane variation due to zooming and has a focusing action, and a fifth lens unit having a fixed negative refractive power. Double viewfinder optical system.
眼レンズを介して観察する際、物体側より順に該対物レ
ンズは固定の正の屈折力の第１群、可動の負の屈折力の
第２群、固定の正の屈折力の第３群、可動の正の屈折力
の第４群、そして固定の負の屈折力の第５群の５つのレ
ンズ群を有し、該第２群と第４群を光軸上移動させて変
倍及び合焦作用を行っていることを特徴とする変倍ファ
インダー光学系。2. When observing an object image formed by an objective lens through an eyepiece lens, the objective lens has a fixed positive refractive power first group and a movable negative refractive power second group in order from the object side. A third lens unit having a fixed positive refractive power, a fourth lens unit having a movable positive refractive power, and a fifth lens unit having a fixed negative refractive power; A variable-magnification finder optical system characterized in that the fourth group is moved on the optical axis to perform a variable-magnification and focusing action.
眼レンズを介して観察する際、物体側より順に該対物レ
ンズは固定の正の屈折力の第１群、可動の負の屈折力の
第２群、可動の第３群、固定の正の屈折力の第４群、可
動の正の屈折力の第５群、そして固定の負の屈折力の第
６群の６つのレンズ群を有し、該第２，第３，第５群を
光軸上移動させて変倍及び合焦作用を行っていることを
特徴とする変倍ファインダー光学系。3. When observing an object image formed by an objective lens through an eyepiece lens, the objective lens has a fixed positive refractive power first group and a movable negative refractive power second group in order from the object side. And a movable third group, a fixed positive refractive power fourth group, a movable positive refractive power fifth group, and a fixed negative refractive power sixth group, six lens groups, A variable power finder optical system in which the second, third, and fifth groups are moved on the optical axis to perform zooming and focusing.
おける前記対物レンズの焦点距離をｆｗとするとき ０．４＜｜ｆ２／ｆｗ｜＜０．６ なる条件を満足することを特徴とする請求項１，２又は
３の変倍ファインダー光学系。4. When the focal length of the second lens unit is f2 and the focal length of the objective lens at the wide angle end is fw, 0.4 <| f2 / fw | <0.6 is satisfied. The variable magnification finder optical system according to claim 1, 2, or 3.
を有していることを特徴とする請求項１，２又は３の変
倍ファインダー光学系。5. The variable power viewfinder optical system according to claim 1, wherein the first lens unit has at least one negative lens.
面を向けたメニスカス状の負レンズと２つの正レンズよ
り成り、前記第２群は２つの負レンズより成り、その他
のレンズ群は全て単一レンズより成っていることを特徴
とする請求項１，２又は３の変倍ファインダー光学系。6. The first group comprises, in order from the object side, a meniscus negative lens having a convex surface facing the object side and two positive lenses, and the second group comprises two negative lenses, and the other lens groups. The variable-magnification viewfinder optical system according to claim 1, wherein all are made of a single lens.
とプラスチック材より成る正レンズとを有し、前記第２
群はプラスチック材より成るレンズで構成していること
を特徴とする請求項１，２又は３の変倍ファインダー光
学系。7. The first group has a positive lens made of a glass material and a positive lens made of a plastic material, and the second group
4. The variable power viewfinder optical system according to claim 1, wherein the group is composed of a lens made of a plastic material.
記変倍ファインダー光学系を装着する変倍部を有する撮
影レンズ中の可動レンズ群と機械的に連結して移動して
いることを特徴とする請求項１，２又は３の変倍ファイ
ンダー光学系。8. A movable lens group in the objective lens is mechanically coupled to a movable lens group in a photographing lens having a variable power unit for mounting the variable power finder optical system, and is moved. The variable magnification finder optical system according to claim 1, 2, or 3.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6290436A JPH08129202A (en) | 1994-10-31 | 1994-10-31 | Variable power finder optical system |
| US08/513,557 US5774275A (en) | 1994-08-30 | 1995-08-10 | Variable magnification viewfinder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6290436A JPH08129202A (en) | 1994-10-31 | 1994-10-31 | Variable power finder optical system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08129202A true JPH08129202A (en) | 1996-05-21 |
Family
ID=17756013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6290436A Pending JPH08129202A (en) | 1994-08-30 | 1994-10-31 | Variable power finder optical system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08129202A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09159917A (en) * | 1995-12-12 | 1997-06-20 | Copal Co Ltd | Rear focus type zoom lens |
| EP1607785A3 (en) * | 2004-06-14 | 2007-01-31 | Sony Corporation | Zoom lens and image pick-up apparatus |
| JP2007206164A (en) * | 2006-01-31 | 2007-08-16 | Canon Inc | Variable power finder and imaging apparatus using the same |
| KR100975300B1 (en) * | 2007-03-28 | 2010-08-12 | 후지논 가부시키가이샤 | Variable-power optical system and imaging device |
| WO2013027363A1 (en) * | 2011-08-25 | 2013-02-28 | パナソニック株式会社 | Zoom-lens system, interchangeable lens device, and camera system |
-
1994
- 1994-10-31 JP JP6290436A patent/JPH08129202A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09159917A (en) * | 1995-12-12 | 1997-06-20 | Copal Co Ltd | Rear focus type zoom lens |
| EP1607785A3 (en) * | 2004-06-14 | 2007-01-31 | Sony Corporation | Zoom lens and image pick-up apparatus |
| US7256945B2 (en) | 2004-06-14 | 2007-08-14 | Sony Corporation | Zoom lens and image pick-up apparatus |
| JP2007206164A (en) * | 2006-01-31 | 2007-08-16 | Canon Inc | Variable power finder and imaging apparatus using the same |
| KR100975300B1 (en) * | 2007-03-28 | 2010-08-12 | 후지논 가부시키가이샤 | Variable-power optical system and imaging device |
| WO2013027363A1 (en) * | 2011-08-25 | 2013-02-28 | パナソニック株式会社 | Zoom-lens system, interchangeable lens device, and camera system |
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